For many people, the EVO is an excellent phone, but extremely weak battery life is a huge detractor. Now, however, always-helpful user Pingpongboss has posted some instructions over at XDA-Devs for how to use the SetCPU app to significantly increase battery life. How significantly? He estimates that he could get 64 hrs with the screen off on a full charge. Pretty impressive stuff. Before and After graphs:

The key is disabling Perflock – a bit of code by HTC that keeps the CPU running at a set speed, regardless of usage.